Underreamer.



J. W PlPPlN. f I UNDER'REA-MER. APPLICATION FILED SEPT-23, 1915.

171 I Patented 11613, 1916.

WITNESSES; INVENTOR v ATTORNEYS men;

JOHN WILLIAM PIPPIN, OF BROWIN'WOOD, TEXAS.

UNDERREAMER.

Specification of Letters Patent.

Application filed September 23, 1915. Serial No. 52,165.

To all whom it may concern: I

Be itknown that I, JOHN W. PIPPIIv', a citizen of the United States, and a resident of Brownwood, in the county of Brown nations, constructions, and arrangements herein described and claimed.

-An object of the inyention is to provide a tool of this class which is simple in construction, positive in action, and which em bodies certain elements which give the tool great strength, thereby preventing the breaking of the bits or cutters-when reaming hard rock. A further object of my invention 1s.t0 provide an under-reamer in which the bits.

are held positively in a contracted position while the tool is being lowered through a well casing, until the bits have passed the end of the casing, whereupon they wil l be automatically expanded.

A further object of 'my invention is to provide an under-reamer having expanding bits that do notv require triggers or other similar devices, such as latches, to hold them in contracted position while through-a well casing.

Other. objects and advantages will appear in the following specification, and the novel passing features ofthe inventionwill be particularly pointed out'in theappended claims.

My invention is illustrated in the accom panying drawing forming part of this ap: plication, and in which Figure 1 is a side view of the device showing it in operative position, certain parts of the device being shown in section. Fig. 2

is a longitudinal section through the device, showing the latter in the position it assumes when being lowered through the well casing. Fig. 3 is a side view at right angles to- Fig. 1,'showing the meansof operating the bits, portions of the figure being shown in section. Fig. is a section along the line 44 of Fig. 2. Fig. 5 is a section along the line 55 of Fig. 2. I p

In carrying out my invention, I provide a body portion 1 which is provided with a threaded tapered extension 2 arranged to enter the socket of the usual drill-rod 3.

The body portion" has flat faces at 4 which permit the manipulation of the body portion by means of a wrench;

' Patented une 13, 1191s.

As will be seen from the drawings the body portion 1 is provided with a slot 5 which extends through from one sideto the other. The lower end of the body portion is provided with a socket-6 which'is tapered as shown. A shoulder 6 is formed in the walls of the socket near the bottom thereof. The body' portion 1 extends below the socket 6 as shownlat 1. The'pur'pose of this extension-will be explained later. The bits for this under-reamer are shown at 7 and 8 respectively. The upper end-of-each of these bits has a semi-conical extension like thatshown at 8 in Fig. 3,-leaving a shoulder like "that shown at 8*. Each of the bits has a 'portlon which is in engagement with the rounded lower end 9 of a rod 10. As. will be seen from Fig. 5, the rounded ends'have lateral extensions 9 into which the ends of screws 11 extend, these screws having shoulders 11 which fit up tightly against the extensions 9.

As will be seen from Fig. 5, each of the bits 1s providedwith a recess on its inner side, these recesses being shown at 7? and The bits are 8 to admit the'exten sions 9% provided with'oblong recesses 7 and 8 into which the heads of the screws 11 extend.

Webs 7 and 8 are provided with openings whichyadmit the screws 11. This construc- 'tion gives the two hits a pivotal movement around the fulcrum head 9. The screws 11 --however hold the bits to the head so that they .do not fall apart when the tool is removed from the well. I

The rod 10 passes upwardly through a bore12in the body portion 1 and the end extends into. a .bore 13. TherodllO has a threaded portion IO upQn hi ch is mounted a collar 14: which is threaded to engage the threads 10 and which may be adjustably moved along the rod 10. A spring 15 bears at one end on this adjustable collar or nut, and at the other end at-the bottom of' the slot 5. The tendency of the spring 15, therefore, it will be seen, is to force the rod 10 upwardly. r From the foregoingdescription of, the various .parts of the device, the operationthereof, may be readily understood.

' In Fig. 2 I have shown a-well casing 16 I .which is provided with a casing shoe 17 at casing; the bits 7 and 8 are held together by means of a spring split ring 18. This ring will engage the top of the casing and will be held back while the tool will pass down into the interior of the casing. When-the spring ring 18 passes off from the bits '2' and 8, the latter will engage the side walls of the casing as shown in Fig. 2', .while the extensions 'Z and 8 will engage the shoulders 6 which are formed by the walls of the socket 6. This prevents any upward movement of. the rod and hence does not tend to expand the bits while the latter are being lowered through the casing. There is, therefore, no tendency to bind, and the tool may be easily lowered into place. In order to prevent the upper portions of the bits from spreading toofar, I provide a screw 19 in one of the members provided with a lock nut 20, so that the lower portion of'the other bit may be adjusted up close to the desired point, when passing through a casing of given size. It willbe obvious that this screw 19 may be turnedso as to adjust the bits for easily passing through casings of various sizes: The lock nut 20 holds the screw in its adjusted position.

When the bits pass theend of the casing, 2'. 6., the shoe 17 so that the outer sides of. the bits are not now held inwardly by contact with the casing, the spring 15 tends to pull the rod l0 'upwardly, and this forces inwardly the upper ends of the bits until they r .ride off from theshoulder 6 and into the tapered sockets Ginto which the upper ends of'the bits are'suddenly and forcibly drawn bymeans ofthespring. The apparatus isnow in the positionshown-in Fig. 1, that is -to say, the bits have been expanded so'as tocontinue the cutting or under-reaming of t the bore. r v I .In order to compress the spring 15 andto move the rod 10 downwardly, thereby. forcing the upper ends ofv the bits out of the socket 6, I provide a handle or lever 21 to which is connected a bent link 22, the latter having an end which enters the slot 5 and which surrounds'the rod. 10 and bears on the nut or collar 141.

It will'beseen that I have provided an expanding bitwhich' is held rigidly in position while it is being inserted and is passingthrough the casing, but which will expand automatically when the end of the casing is reached. The device-is simplified in that the spring 15 which exerts tension on the rod 10, tends to hold the upper end. of the I bits' against the shoulder 6% as explained, andials'o' tends to draw the bits into the tapered socket when the bits have cleared the end of the casing. It will also be noted that the screws 11 may be'screwed up tight against their shoulders-11 so there will be no danger of their coming out. The heads of these screws are countersunk in the openings 7 and 8 and therefore they arenever- 'in' danger of coming into contactwith the walls of the casing.

Another feature to which I desire to call attention is the fact that, the shoulders 7 and 8 are forced up into engagement with the shoulders 6*, these lattershouldersbeing the same that engage the upper 'ends of *the bits to hold the latterein position when the bits are being passed through the casing.

v The nut 14: is fastenedby a pin to the rod 10 so it cannot work away from the proper position. The spring 15 is compressed when the bits are out of the socket and the rod is in its lowest position. This prevents the bit top points from being pulled out below the lower end of the extension 1 which as will be seen forms virtually a sleeve projectingbelow the socket and which keeps the bits from spreading apart at their upper. ends and leaving the'socket entirely.

I claim 1. An under-reamer having a body por tion provided with a slo t,.a spring disposed within the slot, a longitudinal bore disposed centrally of the body portion and intersecting the slot, a movable rod disposed in said'bore,-said body portion having a tapered socket at its lower end and said spring being arranged to bearupon a portion of the rod to hold'it normally in an upper position, a plurality of pivotally .mounted. bits carried at the lower end of said rod, said body portionbeing provided .with a shoulder adjacent to the lower edge ofthe socket adapted to be engaged by the upper portions of the bitsfor preventingthe expansion of the same, and means for spacing the lower ends of'the bits apart.

2. An under reainer comprising a body portion having a central longitudinal bore, a transverse slot intersecting said' bore, a longitudinal rod disposed within said bore, bits fulcrumed on the end of said rod, means carried by the .rod for preventing the displacement of the bits, said body portion having a tapered socket at its lower end and being provided with'shoulders adjacent 'to the lower end of the socket, and a set screw carried byone of said bits for spacing the bits apart. 1'

' 5. In an under-reamer, a cylindrical body portion provided with a. central bore, a

each of said bits being provided with an opening, a screw arranged to extend through each of said openings into the red, the heads of the screws preventing the displacement of the bits from the rod.

.4. In an under-reamer, a body portion provided with a central bore and having atapered socket, a rod disposed within said central bore and beingprovided at its end with a pair of oppositely extending screws, a plurality of bits each of said bits having a recess on one side arranged to pivotally engage a portion of the rod, and a recess on the opposite side registering with said first-named recess, thereby leaving a web between the two recesses, said web being provided with an opening arranged to receive the body portion of the screw, the head of the screw engaging a portion of the web, thereby preventing displacement of the bits.

5. In an under-rearner, a body portion provided with a central bore and having a tapered socket, a rod disposed within said central bore, and being provided at its end with oppositely extending screws, a plurality of bits, each of said bits having a recess on one side arranged to pivotally engage a portion of the rod, and a recess on the opposite side registering with said first named recess, thereby leaving a web between the two recesses, said web being provided with an opening arranged to receive. the

'one of said bits being provided with an adjustable set screw for spacing the lower portions of the bits apart. .1

6. In an under reamer, a body portion provided with a central bore, said body portion having a cylindrical extension at its lower end, and a tapered socket extending upwardly above said cylindrical extension, and a shoulder disposed at the lower end of said tapered socket and at the upper end of the inner'wall of the cylindrical. extension, a longitudinally movable rod disposed within said central bore, bits fulcrumed on the lower end of said rod, the upper ends of the bits being arranged to engage the inner walls of the cylindrical extension'when the movable rod is in'its lower position, thereby preventing the displacementof the bits, and

means for spacing the lower portionsof the bits apart. I

JOHN WILLIAM PIPPIN. Witnesses: v

W. R. PRUITT, F. Gr. BOZEMAN. 

